It is common practice in the construction industry to shore newly poured concrete slabs with a temporary support frame. For large slabs, such as those forming building floor structures, a number of shoring frames must be used. Generally, the support frames remain in place until the slab has cured sufficiently to allow the safe removal of the frame(s). Prior art shoring frames have generally comprised a pair of legs that are laterally spaced apart and interconnected by suitable bracing members, such as horizontal ledgers. The bracing members are welded, or otherwise permanently fixed, to the legs. Typically, the legs have screwjacks at one or both ends which can be adjusted to fix the height of the frame to the desired height of the slab.
When it is desired to pour a concrete a slab, a number of spaced apart frames are generally interconnected to form a shoring tower. The frames must be lifted into place and cross braces are generally secured between adjacent frames to interconnect the frames to form a tower. To the top of each leg in the tower can then be secured cross beam joists that support a slab form or concrete mold. The screwjacks are then adjusted until the structure is level, at the appropriate height, and securely supported at all points. Once the concrete has been poured, the tower remains in place for several days, or longer, until the slab has set. Each supporting tower is then disassembled in the reverse order of the assembly and removed from the site, or to another location. Commonly owned U.S. Pat. No. 4,470,574, which is incorporated herein by reference, discloses a typical prior art shoring frame and tower system.
The shoring towers or structures of the prior art have several disadvantages. The frames are large and unwieldy since they are welded as one piece and not adjustable. Depending on their height, it may take two or more people to place or remove them. The frames serve only one function. If single post shores are needed for reshoring the slab, they must be provided separately, and be transported to the site and separately installed after the frames and/or towers have been disassembled. This adds to the cost of constructing concrete slabs by requiring separate shoring components for shoring frames and single post shoring.